I am restoring an E Howard master-slave clock system circa 1930. I have not yet been able to access the interior of the master clock (because the key to the door is lost). I am trying to identify the model number and gather information on the principal of operation. I am familiar with the Synchronome and Gents clocks (the impulse method of pendulum maintenance, signals to the slave dial, etc) and wonder E Howard used the same or a similar technique. I have uploaded an image of the clock; dimensions are: 59"h x 20"w x 9"d. Thanks in advance.